00:01
Hello students in this portion we are given that a ray of light enters into an equiangular glass prism at an angle of incidence which is equal to 14 .9 degrees and we have to calculate both the angles of reflection and both subpoens.
00:14
So we have to calculate theta 1 r which is this angle and we have to calculate theta 2 r which is this angle.
00:23
So first of all using the snl's law which says that the reflective index of medium 1 multiplied by the sine of angle, sign of the angle with the normal in that region would be equal to the sign, the refractive index from medium to multiplied by the sign of the angle of reflection.
00:41
So, substituting the values in this equation, in order to obtain, are theta 1 r.
00:48
So that would be equal to n1, that is the n of air, multiplied by the sine of theta, theta 1r which is theta 1i which is given in the equation that would be equal to these reflective index of glass multiplied by the sign of the angle this theta 1r so this is the formula in this equation we have to calculate theta 1 r so substituting the value that is equal to 1 .0 multiplied by the sign of the angle theta 1i that is equal to 40 .9 divided by the reflective index of glass that is 1 .5 and that would be equal to sine of theta 1 r so calculating this so calculating this our angle theta 1 r which is coming out to be approximated to 25 .8 degrees so this we have calculated the first angle of reflection that is theta 1 r this we have calculated now we have to calculate this theta 2 r in order to calculate that we need this angle theta 2i so for that we can use the that we are given an equio equi angular prism which means all the angles are 60 degrees and we can calculate this alpha and beta so first of all we are given that this this is a normal to this plane so this angle would be equal to 90 degrees and we have calculated theta 1 r so this means that that that that angle that is theta 1 r plus angle would be equal to 90 degrees.
02:28
So, alpha would be equal to 90 degrees minus theta 1r, that is 25 .8 degrees.
02:36
From this, our alpha is coming out to be approximated to 64 .15 degrees.
02:45
So this is the value of our angle alpha.
02:48
Here we have calculated our angle alpha.
02:50
From this, we can calculate the angle beta that would be by the formation of this this triangle, let us name a, this point b and this point c.
03:01
As all the angles of the triangle sum into 180 degrees, so angle 60 plus alpha plus beta would be equal to 180 degrees and we have calculated, we know that alpha plus beta plus 60 degrees would be equal to 180 degrees that is the total sum of a triangle...